Euphorbia milii plant named ‘Kronos’

ABSTRACT

A new distinct cultivar of  Euphorbia milii  plant named ‘Kronos’, characterized by its light red to red-purple floral bract color from 50C to 58B; very low and bushy plant form; vigorous growth habit; larger, green flowers on thick gray-brown peduncles, RHS 199B.

Latin name of the genus and species of the plant claimed: Euphorbiamilii Desmoul.

Variety denomination: ‘Kronos’.

BACKGROUND OF THE INVENTION

The present Invention relates to a new and distinct cultivar ofEuphorbia milii plant, botanically known as Euphorbia milii Desmoul,commonly known by the name Crown of Thorns, and hereinafter referred toby the name ‘Kronos’.

The new Euphorbia milii is a product of a planned breeding programconducted by the Inventor, Steen Thomsen, in Haarslev, Fyn, Denmark. Thenew Euphorbia milii originated from a cross made in 2001 by the Inventorwith unnamed cultivars of Euphorbia milii Desmoul. The male and femaleparental cultivars are unnamed, unpatented seedlings of Euphorbia miliiDesmoul. The Inventor selected the new Euphorbia milii cultivar as asingle plant from the progeny of the above crossing in 2001 on the basisof its flower color and compact, freely branching habit. Plants of thenew Euphorbia milii are small, compact and have a unique color, largeleaves and abundant medium sized flowers.

A sexual reproduction of the new cultivar by terminal cuttings taken andpropagated and trial production batches at Hjortebjerg Nurseries,Denmark, has shown that the unique features of this new Euphorbia miliiare stable and reproduced true to type in many successive generations.

BRIEF SUMMARY OF THE INVENTION

The following traits have been repeatedly observed and are determined tobe the unique characteristics of ‘Kronos’. These characteristics incombination distinguish ‘Kronos’ as a new and distinct cultivar:

1. Light red to red-purple floral bract color from 50C to 58B.

2. Very low and bushy plant form.

3. Vigorous growth habit.

4. Larger, green flowers on thick gray-brown peduncles, RHS 199B.

Plants of the cultivar ‘Kronos’ can be compared to plants of thecultivar Euphorbia milii ‘Themis’ (unpatented). In side-by-sidecomparisons conducted by the Inventor in Haarslev, Denmark, plants ofthe cultivar ‘Kronos’ and the cultivar ‘Themis’ differ in the followingcharacteristics:

1. Plants of the new Euphorbia milii have light red to red-purplecolored bracts and staminate cyathia with orange glands.

2. Plants of the new Euphorbia milii have larger dark green leaves than‘Themis’.

3. Plants of the new Euphorbia milii have shorter and stiffer pedunclesthan plants of the cultivar ‘Themis’.

4. Plants of the new Euphorbia milii are more compact and less branchedthan the plants of the cultivar ‘Themis’.

Plants of the cultivar ‘Kronos’ have not been observed under allpossible environmental conditions. The phenotype may vary somewhat withvariations in environment such as temperature, light intensity, daylength, and fertility level without, however, any variance in genotype.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying color photographs illustrate the overall appearance anddetails of flower form, color and structures of the new cultivar,showing the colors as true as it is reasonably possible to obtain incolor reproductions of this type. Colors in the photographs may differslightly from the color values cited in the detailed botanicaldescription, which more accurately describe the actual colors of the newEuphorbia milii.

The first photograph shows a full view of a typical full flowering plantof ‘Kronos’, as grown in an 11 cm pot.

The second photograph shows a close up of the young and older floralcymes of ‘Kronos’.

DETAILED BOTANICAL DESCRIPTION

In the following description, color references are made to The RoyalHorticultural Society Colour Chart, 4^(th) edition, where general termsof ordinary dictionary significance are used. Plants were grown undergreenhouse conditions. Plants used for this description were grown forabout 17 weeks after cutting and produced in 6 cm pots. Other pot sizescan be used and the plants are intended for indoor use or as a beddingplant in temperate climates while it is a perennial garden plant intropical and subtropical areas.

Botanical classification: Euphorbia milii Desmoul. ‘Kronos’.Euphorbiaceae, Spurge family.

Parentage:

Female parent.—Unnamed seedling plant of Euphorbia milii.

Male parent.—Unnamed seedling plant of Euphorbia milii.

Propagation:

Type cutting.—Terminal vegetative cuttings taken from plants kept in thevegetative stage by shading and high temperatures (25 C).

Time to initiate roots.—About 10 to 14 days at 18 to 21 C in tunnels ina greenhouse.

Root description.—Fine, well branched.

Plant description:

Form.—Perennial plant with upright plant habit. Euphorbia milii ‘Kronos’flowers in cymes with cyathia subtended by colored bracts. Freelybranching with about 3 lateral flowering branches forming at every node;dense and bushy. Stems are square to pentagonal with ridges—about 10 mmthick at the base. By each node appears groups of thorns: 1 large 12 mmand 4-5 smaller 5 mm. Young thorns are green: 148A; while the older onesbecomes stiffer and changes color to gray (199B).

Crop time.—After rooting, about 17 weeks are required to producefinished flowering plants in 6 cm pots.

Plant height (soil level to top of plant plane).—About 12 cm. Width: 21cm.

Vigor.—Vigorous growth rate.

Foliage description: Leaves alternate, single, obovate, entire. Length:12 cm. Width: About 40 mm. Apex: acute with a small (1 mm) thorn-likeappendage. Base: cuneate to almost decussate. Texture: smooth, waxy,dull., glabrous. Color: Young foliage, upper and lower surfaces: 146Aand 146C, yellow-green. Mature foliage, upper and lower surfaces: 139Aand 148B respectively. Venation, 148D.

Flower description:

Flower arrangement and shape.—Floral arrangements composed of cymes. Theflowers (cyathia) are starkly reduced so only a circle of 5 glands andthe reproductive organs are present. Subtending the cyathia are twocolored bracts. The flowers are further complicated by the uniquefeature of funnel shaped floral buds appearing at the base of the bractsin two or more layers.

Natural flowering season.—Continuous throughout the spring and summer insubtropical and tropical regions. In colder climates season can beextended by greenhouse production with high temperatures andsupplementary irradiance.

Flower longevity on the plant.—5 to 9 weeks; longevity of individualflowers is highly dependent on temperature and light conditions. Bractsturn green with age. Entire cymes drop after withering.

Inflorescence size.—Diameter: About 3-5 cm, height: 10 cm.

Flowers.—3 mm diameter, Bracts: overlapping at base, ovoid to invertedcordate, approximately 10 mm in length by 17 mm in width; color from 50Cto 58B during development.

Glands.—5, from 25A shiny orange to 28A during development.

Anthers.—Appear after flowers mature; stamen and pollen color 59A,yellow-orange.

Pistil and stigma.—Appear before cyathia mature; color 58B to 58C,greenish-yellow.

Peduncle.—Strength: strong. Length: About 6 cm. Diameter: About 3 mm.Color: 199B, gray-brown at an angle of 45°.

Pedicels.—10 cm long, 2 mm thick; strong; color: 153A, yellow-green.

Weather tolerance: Plants of the new Euphorbia milii have exhibited goodtolerance to draught, rain and wind, however flowering may cease duringcold and dark periods (<15C).

Pest tolerance: Plants of the new Euphorbia milii have exhibited goodtolerance to following fungi: Mildew, and Thivaliopis. Also, they appearto be less infected by Thrips (Franklinellea).

I claim:
 1. A new and distinct cultivar of Euphorbia milii plant named‘Kronos’, as illustrated and described herein.